Hey all. Wifes car has been going thru coolant (maybe 2 liters every 4 months). For the last few weeks, the car has a rough idle, but only lasts about 5-25 seconds. And, in the last few weeks, the idle has been rough longer and longer. So, the other day, I pop the hood, and the coolant is low. I filled it up, and the rough idle went away...any ideas? I can't see where this car would be leaking fluid. There is never a puddle under the car in the garage....? Confused!